Yi-Hua Chen, Ph.D., of Tai Pei Medical University, Taiwan, and his colleagues used data from the Taiwan National Health Insurance Research Data set and examined the records from 1,016 epileptic women who delivered a child between 2001 and 2003. Out of these, 503 women had had seizures during pregnancy and 513 did not.
A control group of 8,128 women who gave birth during the same years and were of the same age, but did not have epilepsy or any chronic disease were chosen to compare the results.
The study showed that women who had seizures during pregnancy had a 1.36-fold greater risk of having a low-birth-weight baby (weighing less than 2,500 grams), a 1.63-fold increased risk of giving birth pre-term (before 37 weeks) and a 1.37-fold increased risk of having a baby who was small for gestational age (having a birth weight below the 10th percentile for age) when compared to women without epilepsy.
Also, the chances of women having seizures during pregnancy to have a baby who was small for gestational age were 1.34 times greater than epileptic women who did not have seizures.
The authors said that some of the research conducted earlier had reported a link between adverse pregnancy outcomes and mothers' epilepsy.
"Our study further illuminates these conflicting data to suggest that it is the seizures themselves that seem to contribute greatly to the increased risk of infants being delivered preterm, of low birth weight and small for gestational age. For women who remained seizure-free throughout pregnancy, null or mild risk was identified compared with unaffected women," they said.
Various mechanisms may explain the link between seizures and adverse pregnancy outcomes. Trauma caused by a woman's seizures could rupture foetal membranes, thereby increasing the risk of infection and early birth.
Contractions in the uterus during seizures may lead to tension or cause acute injury. But the research done until now is not sufficient to understand how seizures affect the development of a foetus.
"Neonates born pre-term, of low birth weight and small for gestational age may be predisposed to diseases during infancy and later life, highlighting the significance of proper intervention strategies for prevention," the authors said.
The study has been described in the August issue of Archives of Neurology, one of the JAMA/Archives journals.